综合征，，是医学术语，指某疾病出现时经常会同时出现的临床特征、症状、征象，此时医师可针对出现的其中一种表征，警觉可能一并出现的相关变化，然而实际的病原、确定诊断的疾病名称或相关生理变化可能无法确知。而有些过去未知的疾病表现，经过研究后仍然保留症候群的称呼。

英文为Syndrome，本意是指因某些有病的器官相互关联的变化而同时出现的一系列症状。后有指某一些人因相互影响而达成一致的意向。如“斯德哥尔摩症候群”是指在劫持事件中，人质因同情劫匪而同其达成一致，反而帮助劫匪对付警察。

A syndrome is a set of medical signs and symptoms that are correlated with each other and, often, with a specific disease. The word derives from the Greek σύνδρομον, meaning "concurrence". In some instances a syndrome is so closely correlated with a pathogenesis or etiology that the words syndrome, disease, and disorder end up being used interchangeably for them. This is especially true of genetically caused syndromes. For example, Down syndrome, Wolf–Hirschhorn syndrome, and Andersen syndrome are disorders with known pathogeneses, so each is more than just a set of signs and symptoms, despite the syndrome nomenclature. In other instances, a syndrome is not specific to only one disease. For example, toxic shock syndrome can be caused by various toxins; premotor syndrome can be caused by various brain lesions; and premenstrual syndrome is not a disease but simply a set of symptoms.